In recent years, as various types of information has been generated and distributed, damage such as exposure of important information to a third person has occurred due to hacking or information transfer through a wrong path.
In particular, while no defense mechanism is applied to important information such as military information or personal information during transferring the information, when the important information is accidentally transferred to the third person, the third person can easily access the important information, and as a result, costly damage can occur.
In recent years, in order to prevent the important information from being exposed, a technique has been introduced, which encrypts the important information by using a predetermined encryption key and thereafter, transfers the encrypted important information to a counterpart.
However, since such a scheme encrypts the important information itself, the third person can easily recognize whether the corresponding information is the important information, the important information can be easily exposed to the third person.
Although the important information is encrypted, when the important information itself can be easily exposed to the third person, a problem occurs in terms of security, and as a result, a scheme has been introduced, which transfers the important information while concealing the important information on a predetermined image in recent years in order to reduce an exposure possibility of the important information itself.
When the important information is concealed on the image, the security can be more strengthened as compared with the scheme that encrypts the important information itself in the related art in that it is difficult for the third person to easily recognize whether the important information is concealed on the corresponding image.
Accordingly, research into a more advanced data concealment technique for preventing the important information from being easily exposed to the third person is required according to such a technical stream.